From beaa4867eec02e6eb78e9e9ef503d7eff612b068 Mon Sep 17 00:00:00 2001 From: Geoff Levand Date: Tue, 9 Dec 2008 13:14:17 -0800 Subject: [PATCH] fbcon: fix workqueue shutdown Add a call to cancel_work_sync() in fbcon_exit() to cancel any pending work in the fbcon workqueue. The current implementation of fbcon_exit() sets the fbcon workqueue function info->queue.func to NULL, but does not assure that there is no work pending when it does so. On occasion, depending on system timing, there will still be pending work in the queue when fbcon_exit() is called. This results in a null pointer deference when run_workqueue() tries to call the queue's work function. Fixes errors on shutdown similar to these: Console: switching to colour dummy device 80x25 Unable to handle kernel paging request for data at address 0x00000000 Signed-off-by: Geoff Levand Cc: Krzysztof Helt Cc: Geert Uytterhoeven Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/video/console/fbcon.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c index 67ff370d80af..0b2adefe9e3d 100644 --- a/drivers/video/console/fbcon.c +++ b/drivers/video/console/fbcon.c @@ -3531,12 +3531,18 @@ static void fbcon_exit(void) softback_buf = 0UL; for (i = 0; i < FB_MAX; i++) { + int pending; + mapped = 0; info = registered_fb[i]; if (info == NULL) continue; + pending = cancel_work_sync(&info->queue); + DPRINTK("fbcon: %s pending work\n", (pending ? "canceled" : + "no")); + for (j = first_fb_vc; j <= last_fb_vc; j++) { if (con2fb_map[j] == i) mapped = 1;